pratt



(No Model.)

NfW. PRATT.

PNBUMATIC ORDNANGE.

Patented May 1, 1888..

W/UVESSES:

siren grains Afrnrrr rincer TAT. V. PRATT, OF BROOKLYN, ASSIGNOR TO THE PNEUMATIC DYNAMITE GUET COMPANY, OF NEV YORK, N. Y.

PNEUMATiC GRDNANCE.

SPECIFICATION forming part of Letters Patent No. 382,950. dated May l, i888. Appliration tiled January 4, 1886. Renewed September QU, 1887, Serial No. 251,053. (No model.)

To all whom, it may concern: ervoir; @the iringwalvc; d, the projectile; Be it known that I, NAT. XV. PRATT, a eitig, the breech-block through which the projectzen of the United Statesresiding at Brooklyn, ile is passed into the barrel; il., the cut-off valve; inthe countyof Kings and State of New York, z', an airport communicating with the valve- 55 have invented a new and useful Improvement piston if; m, the air-pump; n, its suct.ioirvalve,

in Air-Guns, of which the followingis a speeiand o its delivery-valve.

iication, reference being had to the accompaa is a stop or lug for locking thc airpump nying drawings, forming a part thereof, .in handle in the position shown7 which secures which* the pump-pistonlduring the act of tiring. 6c

ro Figure lis a longitudinal section; Fig. 2, a The ring mechanism is composed vof a transverse section through the line wx, Fig. i. toothed rack, l, that meshes with a toothed Fig. 3 is an enlarged sectional view oi'a device pinion, 6, attached to the firing-valve c and for operating the firing-valve, and Fig. 4 a connected with the spring-plunger 4. rlhe modieation of the cutoff valve actuated by rack l is provided with a scttingtrigger, 8, 65 i5 pressure; Fig. 5, a modification of the cut-off which, 'when set for firing, engages with a revalve actuated by contact of the projectile. leasingtrigger, 2, as shown in Fig. 3.

The invention relates to that class of guns In order that the advantages attending my in which the agent'of force is air orgas under invention may be fully appreciated, I will I compression. suppose, for example, a gun yas heretofore used 7o zo In such class of guns the compressed air or to have a barrel of teu cubic inches capacity gas is contained in a reservoir that eornniuniof bore and a reservoir of ninety cubic inches cates with the breech of the barrel, said eomcapacity, the latter being filled with air 'at munication being madethroughavalve adapt one hundred pounds pressure; on opening ed to deliver a portion -of the compressed air the valve between the reservoir and the barrel 75 or gas at each discharge and close before the the pressure is reduced to ninety pounds by projectile leaves the muzzle of the barrel, the time the projectile dreachesthe muzzle; whereby the reduction of pressure in the resthe valve is closed, audthe ten cubic inches ervoir is commensurate with the amount of air contained in the barrel at ninety pounds press-s or gas required to fill the barrel .as the proure, or ten per cent. of the original volume, is

3o jectile passes through it. rlhis arrangement thrown away with the projectile. In such preserves the remaining air Aunder a reduced case the actual useful work performed by the pressure in the reservoir to be utilizedfor suoair in propelling the shot would be that due ceeding shots,- but the air between the shot to the average pressure in the barrel, which and the valve passes out with each discharge would be one per cent. .of the total force origiy 3 5 and is lost. nally contained in the reservoir, while the air The object of my invention is to avoid such which is thrown away at each shot would equal loss of air by retaining the same in the barrel nine per cent. more,or one per cent of useful and returning it to the reservoir. effect and nine per cent. of waste, at each disl U The invention consists in locating a eut-off charge. To allow of the maximum pressure 4o valve in the bore of the barrel that remains being applied tothe base of the shot and to open until the projectile passes it, when it is retain the barrel full of air at the terminal automatically closed, either by contact of oppressure just before the shot leaves the muzerating mechanism with the projectile or by zle, (referring to the drawings) I arrange a the air-pressure following the projectile inthe cut-off valve, h, in the bore of the gun,that re- 45 barrel of the gun, whereby the air is retained mains open until the projectile d has passed in the barrel at the terminal pressure. it, and is then automatically closed, either by The accompanying drawings are 'merely inL utilizing the pressure ol air in the bore of the tended toillustrate the main essential elements gun, as in Figs.. 1 or 4, for that purpose, or by of a gun by which the invention referred to in contact of the projectile with suitable mcchzou 5o the claims may be practiced, in whichanism, Fig. 5.,

a represents the barrel; b, the air or gas rcs- In the former method the air enters the lIO 2 I esteso port beneath the piston L that is connected to the vr-lve h, the piston being forced upward and the valve closed, ns shown in Fig. 2. By this means the nir that has been delivered pest the fringvelve c into the barrel a is shut up between the ringynlve c and the cutoff valve h after the shot has passed 'the latter and is vnot blown out with 'the shot. To return this highpressnre air so retained to the reservoir, l pinceau air-pump, m, between the barrel a and the reservoir b, so arranged that its suction-vulve h 'is connected with the barrel. and its delivery/valve o .with the reservoir, and by working the pump m the airis returned to the reservoir, and the balance required to re-establislrthe reservoir-pressure to one hundredv pounds (due to loss by lealrages and work done) is drnvfn either through the muzzle-valve hinto the barrel and to the pump, or else through an auxiliary checlevalve (not shown) connected with the outside atmosphere, thus meting a direct saving (not counting loss by leaks or wort: done) or teu per cent. of the originel volume at ninety per cent. ofthe original pressure, equsling .09 of the force originally contained in the reservoir.

l The reservoir retains its original 'volume at ninety per cent. of the original pressure equal-l ing ninety per cent. plus the nine per cent. in the barrel, equzilingj ninety-nineper cent. of the original force still on hand stored up inthe reserroir and barrel, leaving one percent. for the force out into the projectile, which is the greatest amount of useful effect that could be obtained with any system from n barrel and reservoir of the above proportions. ln the ordinary system .nine times as much is thrown awny'as is turned into useful effect, while by my invention such loss is saved and turned into useful effect.

The above figures as to losses and gains tre approximate only, intended to illustrate the difference between the two systems, and not as absolutely correct as to theoretical values. The theoretical curve of the expansion ol' a-ir and the intent lient transformed into power being applicable to both systems, they have been ignored.

,The operation of charging the reservoir and lending and firing the projectile will no doubt be readily understood from the foregoing descrip" ion. However, l will further explain by eimxnerating the successive steps of the saine, es follows: lhe reservoir ,a is charged with air or gas by means of the air-pump m to any desired degree of pressure, the firing-valve cy being closed and held in its closed position by the connected toothed rack and trigger 2. rhe brecehblock y is opened, the projectile inserted in the barrel, the brecch-bloek is then closed, and the gun is ready for discharge. By releasingr the toothed rack l from engage- Inient with the trigger 2 the firing-valve c is suddenly opened by the recoil of the connected raclobar spring, and the reservoir-pressure instantly forces the projectile through the bar rel. This rnelebnr l 'provided with n sepan rated series of teeth, as shown in Fig. 3, the forward series acting to open the valve c, the separating space to allow it to stand wide open, and the rear series acting to close the valve by the continued recoil movement of the, bar. This rear series o f teeth can be omitted, and in such ease the air, both in the barrel and reservoir, will be retained by the action of the cuto valve h, and the firingvalve c be lsubsequently closed by hand.

The object of this construction is to sutou maticell y close the iringvalvc before the projectile leaves the barrel or passes the cutod 8o valve, and the amount of space made between the separated series ofteeth on the raclobar regulates the time ol closing the firing-valve, and should be so regulated es `to canse the valve to remain open until the full el'ect of 85 the initial pressure is obtained,l and be closed before the projectile escapes, or before or coincident with the closing of the cut'ol valve. Vhen the projectile passes the port z', and be i'ore it leaves the muzzle of the barrel, the airpressure enters the port i and through the nie diuin of the piston 7c forces the valve h up Ward, which closes the barrel'and cuts of the escape of the air, when the firing-valve c is closed and the air retained in the borrel is returned to the reservoir b by the pump m. A modification of the means described for operating the cnt-ofi"l valve is shown in Fig. 4, consisting of an auxiliary slide-valve, p, connected to the piston lc, so as to close the porti and prevent the lescape of the pressure acting to close the cutoff valve after the projectile is discharged, whereby the cnt-olf valve is held closed until the air retained in the barrel is returned to the reservoir; or the cut-off valve may be actuated by thc movement of the projeotile through the bore of the gun coming in contact with a lever (shown in Fig. 5) having a toothed sector engaging with a reel: on the eut-oli valve, the depression of the lever by tine myself to any particular type of ningun,

nor to the means described for operating the cutoff valve or charging the airreservoir, es former may be applied te all "known kinds of nir-guns, end may be operated in other automatic ways. The method of shutting up the pressure in the' barrel is also ep plicnble to powdeijguns'to be used forvforking the breech and firing mechanism, extract ing the cartridges on opening thebreech, end for other purposes which will be the subject offfuturc' applications. Therefore W'hnt I claim, and desire to secure b; Let ters Patent, is-

l. A. gunbm'rel provided with a valve for closing the bore situated forward ofthe chargea chamber thereof and actuated by the passage of the projeetilepnst n predetermined point in the. ceri-el beyond tbc valve.

2. The combination, inV a gun, of the barrel rIO ervoir.

provided with a ring mechanism, and avalve for closing the bore situated forward of the charge-chamber thereof and actuated by the passage of the proj ectiie past a predetermined point in the barrel beyond the valve.

3. A pneumatic gun containing the follow- .ing elements: a pressure-reservoir communiwheei upon its shaft, a reciprocating interrupted toothed rackbar intermittently acting on such gear-wheel when moved in either direction, substantially as described.

5. A pneumatic gun provided with a pressurereservoir communicating directly with the barrel, and with a pump or compressor and the barrel through a separate passage fitted with suitable check or stop valves.

NAT. WV. PRATT.

Witnesses: v

CHAs. L.' MOLLER, J. Wi, LAWSON. 

